High-Efficiency and Compact Polarization-Insensitive Multi-Segment Linear Silicon Nitride Edge Coupler

Edge couplers are widely utilized in photonic integrated circuits and vital for ensuring efficient chip-to-fiber coupling. In this paper, we present a high-efficiency compact polarization-insensitive multi-segment linear silicon nitride edge coupler coupling to high numerical aperture fibers. By optimizing the thickness of up cladding introducing air slots transverse direction, have further modified limiting effect mode field. This innovative scheme boasts structure is compatible with existing mature standard processes, total length only 38 μm. We numerically demonstrate that proposed exhibits low loss 0.22 dB/0.31 dB TE/TM modes at λ = 1550 nm. Furthermore, displays wavelength insensitivity within range 1400–1850 nm maintains less than 0.2 manufacturing deviation ±20